Integrated high-voltage-low-voltage DC-DC converter and charger with active filter

Abstract

A high voltage battery system can receive power from an AC grid and deliver power to a low voltage battery system. Embodiments can include an active filter and high voltage to low voltage (HVLV) DCDC converter to reduce harmonics associated with the charger reaching the low voltage battery system and further to stabilize the voltage presented to the HVLV DCDC converter to improve its operating efficiency.

The invention claimed is: 
     
       1. A high voltage battery system comprising:
 a charger circuit comprising:
 a first input switching bridge having an input and an output, the input configured to be coupled to an AC input source, the first input switching bridge being further configured to convert an AC input voltage to an AC voltage having a selected voltage and frequency; 
 a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and 
 a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to a high voltage DC bus; 
 
 a high voltage battery coupled to an output of the charger circuit; 
 an active filter circuit comprising a filter switching bridge and a filter circuit, having an input coupled to the output of the charger circuit and an output, the active filter circuit being operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output; and 
 a high voltage to low voltage DC-DC converter circuit comprising:
 an inverter having an input configured to be coupled to the output of the active filter circuit and an output, the inverter being further configured to convert a received filtered high DC voltage to an AC voltage having a selected voltage and frequency; 
 a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and 
 a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to a low voltage DC bus and being configured to produce a low DC voltage for the low voltage DC bus. 
 
 
     
     
       2. The high voltage battery system of  claim 1  wherein at least one of the first switching bridge and the first rectifier charger circuit comprise a stacked half bridge. 
     
     
       3. The high voltage battery system of  claim 1  wherein the filter switching bridge comprises a stacked half bridge. 
     
     
       4. The high voltage battery system of  claim 1  wherein the filter circuit is a second order low pass filter. 
     
     
       5. A high voltage battery system comprising:
 a charger circuit comprising:
 a first input switching bridge having an input and an output, the input configured to be coupled to an AC input source, the first input switching bridge being further configured to convert an AC input voltage to an AC voltage having a selected voltage and frequency; 
 a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and 
 a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to a high voltage DC bus; 
 
 an active filter circuit comprising a filter switching bridge and a filter circuit, the active filter circuit having an input coupled to the output of the charger circuit and an output coupled to the high voltage DC bus, wherein the active filter circuit is operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output; 
 a high voltage battery coupled to the high voltage DC bus; and 
 a high voltage to low voltage DC-DC converter circuit comprising:
 an inverter coupled to the active filter circuit and an output, the inverter being further configured to convert a high DC voltage to an AC voltage having a selected voltage and frequency; 
 a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and 
 a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to a low voltage DC bus and being configured to produce a low DC voltage for the low DC voltage bus. 
 
 
     
     
       6. The high voltage battery system of  claim 5  wherein at least one of the first switching bridge and the first rectifier charger circuit comprise a stacked half bridge. 
     
     
       7. The high voltage battery system of  claim 5  wherein the filter switching bridge comprises a stacked half bridge. 
     
     
       8. The high voltage battery system of  claim 5  wherein the filter circuit is a second order low pass filter. 
     
     
       9. A high voltage battery system comprising:
 a charger circuit having an input configured to receive power from an AC input source and an output coupled to a high voltage DC bus configured to provide output DC power to a high voltage battery, wherein one or more switching converters of the charger circuit are operable to convert the received power into the output DC power; 
 an active filter circuit having an input coupled to the output of the charger circuit and an output, wherein the active filter circuit is operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output; and 
 a high voltage to low voltage DC-DC converter circuit having an input coupled to the output of the active filter circuit and an output configured to be coupled to one or more low voltage loads, wherein the high voltage to low voltage DC-DC converter is operable to convert a filtered DC voltage received from the active filter to a lower DC voltage provided to a low voltage DC bus. 
 
     
     
       10. The high voltage battery system of  claim 9  wherein the charger circuit comprises:
 a first input switching bridge having an input configured to be coupled to the AC input source and an output, the first input switching bridge being further configured to convert the received power to an AC voltage having a selected voltage and frequency; 
 a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and 
 a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to the high voltage DC bus. 
 
     
     
       11. The high voltage battery system of  claim 10  wherein at least one of the first input switching bridge and the first rectifier charger circuit comprise a stacked half bridge. 
     
     
       12. The high voltage battery system of  claim 9  wherein the active filter circuit comprises a filter switching bridge and a filter circuit. 
     
     
       13. The high voltage battery system of  claim 12  wherein the filter switching bridge comprises a stacked half bridge. 
     
     
       14. The high voltage battery system of  claim 12  wherein the filter circuit is a second order low pass filter. 
     
     
       15. The high voltage battery system of  claim 9  wherein the high voltage to low voltage DC-DC converter circuit comprises:
 an inverter having an input configured to be coupled to the output of the active filter circuit and an output, the inverter being further configured to convert a received filtered high DC voltage to an AC voltage having a selected voltage and frequency; 
 a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and 
 a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to the low voltage DC bus. 
 
     
     
       16. A high voltage battery system comprising:
 a charger circuit having an input configured to receive power from an AC input source and an output, wherein one or more switching converters of the charger circuit are operable to convert the received power into output DC power; 
 an active filter circuit having an input coupled to the output of the charger circuit and an output, wherein the active filter circuit is operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output and wherein an output of the active filter circuit is coupled to a high voltage DC bus configured to provide output DC power to a high voltage battery; and 
 a high voltage to low voltage DC-DC converter circuit having an input coupled to the active filter circuit and an output configured to be coupled to one or more low voltage loads, wherein the high voltage to low voltage DC-DC converter is operable to convert a DC voltage to a lower DC voltage provided to a low voltage DC bus. 
 
     
     
       17. The high voltage battery system of  claim 16  wherein the charger circuit comprises:
 a first input switching bridge having an input configured to be coupled to the AC input source and an output, the first input switching bridge being further configured to convert the received power to an AC voltage having a selected voltage and frequency; 
 a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and 
 a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to the high voltage DC bus. 
 
     
     
       18. The high voltage battery system of  claim 17  wherein at least one of the first input switching bridge and the first rectifier charger circuit comprise a stacked half bridge. 
     
     
       19. The high voltage battery system of  claim 16  wherein the active filter circuit comprises a filter switching bridge and a filter circuit. 
     
     
       20. The high voltage battery system of  claim 19  wherein the filter switching bridge comprises a stacked half bridge. 
     
     
       21. The high voltage battery system of  claim 19  wherein the filter circuit is a second order low pass filter. 
     
     
       22. The high voltage battery system of  claim 16  wherein the high voltage to low voltage DC-DC converter circuit comprises:
 an inverter having an input configured to be coupled to the active filter circuit and an output, the inverter being further configured to convert a received DC voltage to an AC voltage having a selected voltage and frequency; 
 a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and 
 a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to the low voltage DC bus.